Within the context of Lean thinking, quite a lot of attention is given to the proper and smart maintenance of equipment and installations; and for a good reason. Poor maintenance, typically resulting in unplanned down-time, rejects and loss of speed, is still an important cause of poor delivery reliability towards customers. And as a result, indirectly, it may also well be the reason behind high inventory levels and excessive overhead cost to still try being on-time.
Total Productive Maintenance or TPM, therefore, also is a well-known theme among capital-intense (semi-)process industries like for instance chemicals, plastics, metals, energy, paper, food and fast-moving consumer goods. And in more and more cases, TPM (either independently or as a part of Lean) is already well under way. But in this post, I don’t want to focus too much on the phase the equipment is already in operation, but rather before we even install the equipment, viz., the design, choice and purchase of the equipment. If we don’t, lots of problems may later arise because of a lack of Lean thinking in the design and purchasing process of equipment. Time for a change therefore; time to move towards Lean equipment and a monument-free future!
The Problem with Monuments
Too often, while on the gemba, I am confronted with equipment, machines and installations that stand in the way of an integral process. Their cycle times are not at all aligned to the cycle times of upstream and downstream processes. Preferably they just run faster, as that is what often seems to be one of the most important design and purchase criteria. Or they seriously hinder flow, as the fastest machine often also require the largest batches because of their plain size and/or difficult changeovers. Sometimes, installations and machines are so immensely large, they give you the sentiment of a “factory-within-the-factory” (but not in the good sense, like mini-companies or autonomous zones and teams).
I still remember a case whereby a newly bought machine was placed in the middle of the industrial building. Due to its dimensions, it could not be placed anywhere else than there. It didn’t fit on the side, together with other, similar machines, that were positioned there to create as straight and short as possible flows from component manufacturing to surface treatment to assembly. Feeding routes didn’t work anymore and had to be re-designed and re-balanced. Nobody had given thought to the end-of-line stock that was part of our overall production system. So, as a group of visitors admired this new machine, I provocatively turned my back on the machine and instead looked at the pile of work-in-process it had produced. When I was asked why I didn’t look at the machine, I answered: “Because I’m wondering whether anyone has given even the slightest thought to the production system as a whole when designing and buying this machine”.
Such installations, in Lean often described as “monuments”, typically lead to high levels of work-in-process between stages, physically even distancing the subsequent processes in the value stream due to the required space to store all the stuff it spits out into the factory. They are an important cause of long lead times, reduced mix flexibility and low and ineffective reactivity to quality problems and their resolution. They lead to the “factory-within-the-factory” feeling I already spoke about. This physical and mental distance between machines that are part of the same value stream also creates a lack of autonomy on the shop floor, communication issues and adversity between teams, whereby teams finger-point each other instead of doing kaizen to improve customer-relevant results.
I think we can do a better job in the equipment design and purchase process. We should consciously evaluate our potential design and purchase options with Lean thinking in mind. Of course, we already think of Design-for-Service or Design-for-Maintenance. But do we already consider aspects like Design-for-(Continuous)-Flow, Design-for-Flexibility or even Design-for-Autonomy? Or maybe even more comprehensively, Design-for-Lean leading to something we could call “Lean Equipment”?
Some Considerations for Lean Equipment
So, what are some examples that could be considered in the equipment design and purchase process? Without trying to be exhaustive in this blog post, I’ll try to name a few.
- First, Lean equipment should be “right-sized”. This means that its physical footprint should fit the footprint of the equipment immediately upstream and downstream of it. In this way, equipment can (continue to) be positioned in-flow and aligned to the value stream. In such a way, it also enables the possible modular extension of the factory, whereby integral value streams with their work centers can be added, moved, transferred or discontinued without impacting other value streams. It thus provides more strategic flexibility to the company.
- Second, Lean equipment along the flow preferably need to be balanced in terms of cycle times and lot sizes (ideally one). And their changeover time preferably should be in the same range as their cycle time. Only like this a company can truly try to move towards true one piece flow in its various value streams.
- Third, and related to the previous point, give thought to the use of easy exchangeable, standardized tools and molds required by the equipment. This makes them more versatile and will provide flexibility when demand patterns shift and change. Even the machines themselves should be easily movable when new configurations are required in the future. So, don’t make the installation or machine part of your building infrastructure if you can avoid it.
- A fourth aspect, not often considered I notice, is the question whether the equipment is autonomous. I thereby mean autonomous in the sense of “able to detect various problems and to autonomously stop the machine (or at least alert its operators)”. This is known in Lean as autonomation and part of the jidoka pillar. I often see efforts to error-proof (or poka yoke) a machine only after it has been installed and in use for quite some while already. Lean equipment is error-proof by design!
- And of course, the requirements for easy maintainability (to enable autonomous maintenance by operators) are added to this list. Which brings us back again to TPM or Total Productive Maintenance.
Now of course, I do realize that all of this isn’t easy. We already have a lot of capital tied up in our current assets. And we don’t just change to another factory configuration overnight, that’s clear. But as the proverb says: “the best time to plant a tree was twenty years ago. The second-best time is now”. And to continue with another saying: “even a journey of a thousand miles begins with a single step” (Lao Tzu, 600 BC). In short, did you already start up your Lean Equipment program to prepare for a Leaner future? Then now is the time!